CVE-2026-42570

Svelte devalue: DoS via sparse array deserialization

Published Jun 9, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. From version 5.6.3 to before version 5.8.1, devalue.parse could, due to quirks in some JavaScript engines, be convinced to allocate much more memory than was needed when deserializing sparse arrays, leading to excessive memory consumption. This issue has been patched in version 5.8.1.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-77vg-94rm-hx3p Svelte devalue: DoS via sparse array deserialization
History
Type Values Removed Values Added
CPEs cpe:2.3:a:svelte:devalue:*:*:*:*:*:node.js:*:*
Type Values Removed Values Added
First Time appeared Svelte
Svelte devalue
Vendors & Products Svelte
Svelte devalue
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. From version 5.6.3 to before version 5.8.1, devalue.parse could, due to quirks in some JavaScript engines, be convinced to allocate much more memory than was needed when deserializing sparse arrays, leading to excessive memory consumption. This issue has been patched in version 5.8.1.
Title Svelte devalue: DoS via sparse array deserialization
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 24, 2026, 12:07 PM
Reserved
Apr 28, 2026, 5:26 PM
Status
Modified
Published
Jun 9, 2026, 5:17 PM
Modified
Aug 24, 2026, 1:18 PM
Severity
Important
Public date
Jun 9, 2026, 4:12 PM